On Tue, Nov 05, 2013 at 03:55:43AM -0800, Andrew Gallagher wrote:
> From: Andrew Gallagher <andrewjcg@xxxxxx>
>
> Various read operations (e.g. readlink, readdir) invalidate the
> cached attrs for atime changes. However, mounts that have disabled
> atime can avoid this invalidation and any performance cose. This
> patch adds a new function 'fuse_invalidate_atime' modeled around
> the 'touch_atime' function that which performs the various checks
> for noatime situations and avoids the attr invalidation in that case.
Doing it based on "MNT_NOATIME" isn't going to work, unfortunately: the
nameidata in ->follow_link() doesn't contain a valid path. And besides, it's
ugly. So lets just base this on MS_RDONLY, which implies NOATIME already.
Updated, untested patch follows.
Thanks,
Miklos
---
fs/fuse/dir.c | 14 ++++++++++++--
fs/fuse/file.c | 4 ++--
fs/fuse/fuse_i.h | 2 ++
3 files changed, 16 insertions(+), 4 deletions(-)
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -112,6 +112,16 @@ void fuse_invalidate_attr(struct inode *
get_fuse_inode(inode)->i_time = 0;
}
+/**
+ * Mark the attributes as stale due to an atime change. Avoid the invalidate if
+ * atime is not used.
+ */
+void fuse_invalidate_atime(struct inode *inode)
+{
+ if (!IS_RDONLY(inode))
+ fuse_invalidate_attr(inode);
+}
+
/*
* Just mark the entry as stale, so that a next attempt to look it up
* will result in a new lookup call to userspace
@@ -1371,7 +1381,7 @@ static int fuse_readdir(struct file *fil
}
__free_page(page);
- fuse_invalidate_attr(inode); /* atime changed */
+ fuse_invalidate_atime(inode);
return err;
}
@@ -1404,7 +1414,7 @@ static char *read_link(struct dentry *de
link[req->out.args[0].size] = '\0';
out:
fuse_put_request(fc, req);
- fuse_invalidate_attr(inode); /* atime changed */
+ fuse_invalidate_atime(inode);
return link;
}
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -687,7 +687,7 @@ static int fuse_readpage(struct file *fi
SetPageUptodate(page);
}
- fuse_invalidate_attr(inode); /* atime changed */
+ fuse_invalidate_atime(inode);
out:
unlock_page(page);
return err;
@@ -716,7 +716,7 @@ static void fuse_readpages_end(struct fu
fuse_read_update_size(inode, pos,
req->misc.read.attr_ver);
}
- fuse_invalidate_attr(inode); /* atime changed */
+ fuse_invalidate_atime(inode);
}
for (i = 0; i < req->num_pages; i++) {
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -788,6 +788,8 @@ void fuse_invalidate_attr(struct inode *
void fuse_invalidate_entry_cache(struct dentry *entry);
+void fuse_invalidate_atime(struct inode *inode);
+
/**
* Acquire reference to fuse_conn
*/
--
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